[aravis] gv_device: check for number of stream channels before creating stream object.

[Emmanuel Pacaud <emmanuel src gnome org>]

commit db7926bb4af6aa90b79bb2f7cdaac5c216022846
Author: Emmanuel Pacaud <emmanuel gnome org>
Date:   Fri May 6 10:42:26 2011 +0200

    gv_device: check for number of stream channels before creating stream object.

 src/arvgvdevice.c |    7 +++++++
 1 files changed, 7 insertions(+), 0 deletions(-)
---
diff --git a/src/arvgvdevice.c b/src/arvgvdevice.c
index b5410f4..bc6c843 100644
--- a/src/arvgvdevice.c
+++ b/src/arvgvdevice.c
@@ -569,9 +569,16 @@ arv_gv_device_create_stream (ArvDevice *device, ArvStreamCallback callback, void
 	const guint8 *address_bytes;
 	guint32 stream_port;
 	guint packet_size;
+	guint32 n_stream_channels;
 	GInetAddress *interface_address;
 	GInetAddress *device_address;
 
+	arv_device_read_register (device, ARV_GVBS_N_STREAM_CHANNELS_OFFSET, &n_stream_channels);
+	arv_debug ("device", "[GvDevice::create_stream] Nimber of stream channels = %d", n_stream_channels);
+
+	if (n_stream_channels < 1)
+		return NULL;
+
 	if (!io_data->is_controller) {
 		arv_debug ("device", "[GvDevice::create_stream] Can't create stream without control access");
 		return NULL;